When I was in elementary school, words that appeared on spelling tests seemed to follow patterns.
One week’s list would have several words that followed the “‘i’ before ‘e’ except after ‘c'” rule, while another week’s list would feature words with Greek roots, like “telephone” or “telekinesis.”
Of course, the authors of spelling textbooks did this on purpose. If you’re trying to spell a word you don’t know, you’ll have an easier time if you know and can reference common spelling rules.
Because you don’t have your elementary school spelling book handy, this infographic from Market Domination Media and HubSpot can be your adult equivalent. It lists several techniques to employ when you have to spell a word you don’t know—and you don’t want to turn to Google, dictionary.com or autocorrect. (You don’t want to rely on technology for everything, do you?)